Handover optimization during 5G to 4G mobility

ABSTRACT

A system and method may improve service setup time and reliability for user equipment (UE) fallback procedures in cellular networks. Logic in the UE may define an event to trigger a measurement report and send that measurement report to the base station upon initiating fallback procedures. This event and measurement report may allow the 5G base station (g-NB) to know which frequency is going to be the best choice at the time of setting up the voice service by looking at radio signal strength indicators coming from the 5G UE for each frequency in the measurement report. Incorporating the measurement report process into the logic of the UE for call setup that also includes the fallback process for may result in substantially faster call setup time as well as better voice call success rate.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. The work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

Fifth Generation or “5G” cellular networks offer significantimprovements over earlier cellular network designs including much higherdata rates (1-20 Gigabits per second), much lower data latency (e.g., 1millisecond), and increased capacity as the network expands. 5G consistsof an array of technologies to meet these goals including antenna andcellular tower design, a larger frequency spectrum, and softwareimplemented by various carriers to improve the capabilities of theirsubscribers. For example, carriers may modify any one of the processesinvolved in cellular network management (e.g., user equipment (UE)registration, etc.) to make slight improvements in data rates, latency,or network capacity that, collectively, contribute significantimprovements in cellular network improvements.

One aspect of current 5G networks is their reliance on 4G networks toprovide some services such as voice when those service are not availablein a 5G base station. Evolved Packet System (“EPS”) Fallback enablesphones to use the 5G core with “new radio” (NR) before all 5G voicefeatures are in place on the UE and in Next Generation Radio AccessNetworks (NG-RAN) and before the NG-RAN is dimensioned and tuned for the5G voice service. During call establishment, the UE is moved from NR(5G) to LTE (4G) and the voice service is then established on 4G. Insum, 5G UE initiates the voice service in 5G, but fulfills the serviceon 4G.

However, this handoff procedure significantly increases the chances ofvoice service delays and failures when the 4G LTE signal strength isintermittent, weak and/or causes loss-of-signal on the 5G UE. Theseproblems typically occur in UEs making Voice over New Radio (VoNR) callsfrom the 5G cell edge. These calls have a high risk of experiencing badcall quality, and in the worst case, a call drop. To prevent this the UEis forced during the voice call setup towards 5G core network (5GC) toswitch to a LTE/EPS connection where the radio conditions are better forthe voice service. The same procedure for which the term “EPS Fallback”was coined by 3GPP also applies when the UE is served by a 5G cell thatis not configured/not optimized for VoNR calls or when the UE does nothave all needed VoNR capabilities.

EPS fallback may be accomplished in a few ways. For example, the 5Gradio connection may be released after the initial voice service attemptis successfully finished. The base station may then send a controlsignal to the UE for reselecting to a 4G cell where a new radioconnection is started for the Voice Over LTE (VoLTE) call. In this case,the UE context is transferred from the AMF to the MME over the N26interface. Another example of EPS fallback may include a 5G-4G inter-RAThandover. Here, the session management and user plane tunnels in thecore network are handed over from SMF/UPF to MME/S-GW. This method maybe realized with the GTPv2 Forward Relocation procedure on N26interface. Each of these methods may incur an additional call setupdelay of approximately 2 seconds.

These failings of the 5G/4G “fallback” process present a technicalproblem. For example, it is often difficult for the 5G base station toinitiate the 4G service with an intermittent or weak 4G signal. Further,once a 5G UE succeeds in starting voice services over a weak 4G LTEsignal, then ends that service over 4G or the service fails due to theweak signal, the 5G UE may continue the service and all other services(e.g., data services, location services, etc.) over the 4G LTE band(e.g., mid-band: 2.5 GHz) instead of switching back to a 5G low-band forthose other services. In addition to network latency differences between4G and 5G connections, having the 5G UE camped or “stuck” on a 4Gnetwork could add extra delay to services such as voice call setup andmay also contribute to additional service failures (e.g., call setupfailures). Additional issues may arise in other critical procedures likeE911 call setup, data sessions (YouTube, Netflix, etc.), handover from5G standalone (“SA”) to 4G LTE and future 5G Ultra-reliable Low-latencyCommunications (“URLLC”). Current systems may also cause failures infuture services such as Voice Over NR (VoNR).

The EPS fallback decision made by the base station is guided bymeasurement reports from the UE. Past systems include variousmeasurement items such as Reference Signal Received Power or “RSRP,”Reference Signal Received Quality or “RSRQ,” Signal-to-Noise andInterference Ratio or “SINK”) and multiple ways (periodic, eventtriggered) to measure the signal quality of the serving cell andneighbor cells. In Ideal case, a base station shall allow UE to reportserving cell and neighbor cell signal quality and trigger the handoverwith single measurement, but in practice it can create overloadconditions due to unnecessary ping pong handovers. To avoid this, 3GPPspecifications have proposed a set of predefined “measurement report”mechanisms to be performed by the UE (see 3GPP specification 38.331available athttps://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3197).These predefined measurement reports are triggered by “events.” The typeof “event” a UE reports is specified by an RRC control signal messagesent by the base station to the UE. However, because the current systemrelies on the base station to trigger these measurement report events atthe UE, the best information for the fallback procedure will not beavailable when the UE requests call initiation, thus, the EPS fallbackprocedure may still experience setup delays and signal drops.

SUMMARY

The following presents a simplified summary of the present disclosure inorder to provide a basic understanding of some aspects of thedisclosure. This summary is not an extensive overview. It is notintended to identify key or critical elements of the disclosure or todelineate its scope. The following summary merely presents some conceptsin a simplified form as a prelude to the more detailed descriptionprovided below.

To solve the technical problem described above, logic in the 5G UE maysend a measurement report to the 5G base station (i.e., gNB) while the5G SA UE is going through a call setup using VoEPSFB. This new type ofevent and measurement report may convey the most current availablefrequencies (3G, 4G, 4G LTE, etc.) to the 5G base station while the 5GUE is going through a call setup. This measurement report may allow the5G base station (g-NB) to know which frequency is going to be the bestchoice at the time of setting up the voice service by looking at radiosignal strength indicators coming from the 5G UE for each frequency inthe measurement report. That way, a 5G base station can make the rightchoice to automatically send a control signal to the 5G UE to join theoptimal LTE frequency instead of sending a blind choice of any available4G frequency based on prior measurement reports that frequently includeout-of-date information. Using the measurement report sent by the UEupon voice services initiation, the 5G base station may optimallycontrol 5G UE without having available frequencies to support therequested service (e.g., voice services) in 5G NR. The 5G base stationmay cause the 5G UE to move to a strong and reliable radio signalstrength indicated in the measurement report to make voice calls over 4Gusing that stronger signal. As such, the 5G UE may have faster callsetup time by having such enhanced logic in 5G UE so that it proactivelyhelps the 5G base station to assign it to the right frequency during avoice call setup. Incorporating the measurement report process into thelogic of the 5G UE for call setup that also includes the fallbackprocess for 5G UE may result in substantially faster call setup time aswell as better voice call success rate.

In further embodiments, an apparatus for completing a fallback processbetween a base station and a user equipment in a cellular network mayinclude a modified user equipment including a processor and a memorystoring instructions for execution by the processor for the fallbackprocess. The apparatus may include an instruction for determining asignal strength for each of a plurality of frequencies being received bythe user equipment and generating a measurement report including thesignal strength for each of the plurality of frequencies being receivedby the user equipment. The user equipment may also include instructionsfor sending the measurement report to a base station upon sending arequest to initiate a service corresponding to the measurement report.The base station may be configured to automatically send a controlsignal to the user equipment in response to determining that a frequencyfor the service is not supported by the base station. The control signalmay include further instructions for receiving the service at the userequipment by attaching to an optimal one of the plurality of frequenciesat the user equipment based on the signal strengths indicated by themeasurement report.

In still further embodiments, a computer-implemented method may completea fallback process between a base station and a user equipment in acellular network. The method may determine a signal strength for each ofa plurality of frequencies being received by the user equipment andgenerate a measurement report including the signal strength for each ofthe plurality of frequencies being received by the user equipment. Theuser equipment may then send the measurement report to a base stationupon sending a request to initiate a service corresponding to themeasurement report. The method may then receive a control signal fromthe base station at the user equipment in response to determining that afrequency for the service is not supported by the base station. Thecontrol signal may cause the user equipment to receive the service atthe user equipment by attaching to an optimal one of the plurality offrequencies at the user equipment based on the signal strengthsindicated by the measurement report.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures depict a preferred embodiment for purposes of illustrationonly. One skilled in the art may readily recognize from the followingdiscussion that alternative embodiments of the structures and methodsillustrated herein may be employed without departing from the principlesdescribed herein.

FIG. 1 is an illustration of an exemplary system for moving 5G UE to 4GLTE in accordance with the current disclosure;

FIG. 2 is an illustration of an exemplary base station in accordancewith the current disclosure;

FIG. 3 is an illustration of user equipment in accordance with thecurrent disclosure; and

FIG. 4 is an illustration of a flow chart for a method moving 5G UE to4G LTE in accordance with the current disclosure.

DETAILED DESCRIPTION

The present application describes embodiments including various elementsthat are present in a mobile telecommunications network such as modules,blocks, functions, data structures, etc. These elements are not anexhaustive collection of all elements needed to perform the functions ofa mobile telecommunications network (i.e., 5G handoff to a 4G frequency)or the disclosed embodiments. Indeed, the elements associated with thesystems and methods described in this application are only some of thepossible elements that are needed to implement the embodiments. Someembodiments may include more or fewer elements than those that aredescribed with the embodiments, as known by a person having ordinaryskill in the art of mobile telecommunications systems.

The present application describes a technical solution to the technicalproblem of frequency handoff from 5G to 4G when a 5G UE requestsservices that are not supported by the 5G base station and the 5G UEmust switch or “fallback” to a 4G frequency. The present applicationsolves this technical problem by modifying the typical 5G UE fallbackprocess so that the 5G base station no longer relies on blindly choosingany available 4G frequency from prior measurement reports for thefallback procedure. The 5G UE may send a “Measurement Report” to a 5Gbase station (i.e., gNB) at the time of call setup using VoEPSFB. Themeasurement report may convey available LTE frequencies and their signalstrength to the 5G base station upon initiating or requesting voiceservices. This measurement report may allow the 5G base station (g-NB)to know which frequency in LTE is going to be the best choice at thetime of setting up the voice service by looking at radio signal strengthindicators coming from the 5G UE for each frequency in the measurementreport. That way, a 5G base station can automatically send a controlsignal to the 5G UE to join the optimal LTE frequency instead of sendinga choice based on other factors that do not influence service success orbased on no factors at all. Using the measurement report, the 5G basestation may optimally control 5G UE without having available frequenciesto support the requested service (e.g., voice services) in 5G NR. The 5Gbase station may cause the 5G UE to move to a strong radio signalstrength indicated in the measurement report to establish a servicerequiring a previous generation specification (e.g., 4G, 4G LTE, 3G,etc.) or other specification using that stronger signal. The 5G UE maythen have faster call setup time by having such enhanced logic in 5G UEso that it proactively helps the 5G base station to assign it to theright frequency during a voice call setup. Incorporating the measurementreport into the call setup process during a fallback for 5G UE mayresult in substantially faster call setup time as well as better voicecall success rate.

FIG. 1 illustrates a system 100 supporting operation of user equipment(UE) 102 in a cellular communication system generally and, inparticular, facilitating a computer-implemented process for 5G fallbackprocedures between the UE 102 with the system 100 as described herein.The UE 102 may be any electronic device that is capable of sending,receiving, and/or processing a 5G radio signal for communicating datafrom the UE 102 to other UEs (not shown) via the base station 104. Insome embodiments, the UE 102 includes a cellular telephone, asmartphone, a smart watch, an Internet of Things device, a computingdevice, etc. The UE 102 may be categorized or grouped along variouscharacteristics including device capabilities and network services. Forexample, in some embodiments, the UE 102 may include a smartphone UE102A, an Internet of Things UE 102B, etc.

The UE 102 may include a memory 106 storing instructions for executionon a processor 108 to generate and send a measurement report 110 at thetime of call setup. For example, the memory 106 may include a fallbackmodule 106A including various instructions for execution by theprocessor 108 to generate and send a measurement report 110 and a UEvoice services module 107A to request and maintain voice services withthe base station 104 using a base station voice services module 105. Themeasurement report 110 may include data indicating frequencies that arecurrently being received by the UE 102, a signal strength for each ofthose frequencies, an indication of a standard for the signal (e.g., 4GLTE, 4G, 3G, etc.), a duration of signal reception at the UE 102, ameasure of signal reliability either at the UE 102 or other data thatmay be determined from past measurement reports 110, among otherinformation. In some embodiments, the signal strength is indicated indecibel-milliwatts (dBm) in the measurement report. In some embodiments,frequency is indicated on the measurement report 110 in gigahertz (GHz).In other embodiments, frequency may be indicated in any other suitableunits of measurement.

The Radio Resource Control (RRC) protocol is used to control radioconnections between the UE 102 and the base station 104. This protocolmay form some of the instructions of the UE voice services module 107A.A state machine defines states for the UE 102 and guides operation ofthe RRC. Instructions for executing this state machine may bedistributed between the UE 102 and the base station 104, or may form atleast some of the instructions of the voice services module 107A of theUE 102. The different states in this state machine have differentamounts of radio resources associated with them and these are theresources that the UE 102 may use when it is present in a given specificstate. A 5G-configured UE 102 has three different RRC states: inactive,idle, and connected. When the UE 102 is powered up, it is indisconnected mode/idle mode. Upon initially attaching to the basestation 104 or connection re-establishment with the base station 104,the UE 102 moves to the “connected” state. If there is no activity fromthe UE for a pre-configured amount of time, the UE 102 suspends itssession with the base station 104 and moves to “inactive.” In theinactive state, the UE 102 maintains its connection to the base station104, but also minimizes signaling and power consumption. Upon resumingthe session, the UE 102 moves to “connected.” The UE may move to “idle”from “connected” when ending the session or to “inactive” after a periodof time to also minimize power consumption.

Processor-executable instructions stored in the memory 106 (i.e., thefallback module 106A, the UE voice services module 107A, etc.) mayinclude instructions to generate the measurement report 110 and send thereport 110 to the base station 104 in response to initiating voiceservices procedures by the UE 102 generally and the UE voice servicesmodule 107A in particular. These instructions may be incorporated intothe state machine of the RRC protocol. For example, the fallback module106A may include instructions to periodically determine the measurementreport 110 or determine the measurement report 110 in response to aremote or local control signal as part of the RRC state machine. Inother embodiments, the instructions of the fallback module 106A mayinclude periodically or responsively sending only a portion of themeasurement report 110. For example, the instructions of the fallbackmodule 106A may include only sending an indication of the strongestsignal from the measurement report 110, only those that are compatiblewith the capabilities of the base station 104, etc., at the time of callsetup using VoEPSFB.

Each UE 102 may belong to one or more of the UE groups each having itsown user equipment group identification. Thus, each UE 102 may includeits own UE ID and belong to a group of UEs having a single UE group IDassociated with all UEs that are members of the group. For example,internet-of-things UE may have a different UE ID than a smartphone UE,or other types of UE. The UE 102 may be subscribed to a mobile networkoperator (MNO) that maintains the network base station 104. A subscribermay be an entity who is party to a contract with the MNO for access topublic telecommunications services. Different MNOs may support differentnetwork standards and capabilities. While FIG. 1 only shows one basestation 104 and two UE types, the embodiments described herein applyequally to systems having different numbers of base stations,corresponding MNOs, UEs, etc. The UE is able to maintain connectivitybeyond the coverage area 106 of the network base station 104 shown inFIG. 1 despite only the network base station 104 being maintained by anetwork MNO having a contract for telecommunications services with asubscriber corresponding to the UE 102. For example, the UE 102 may moveout of range of the coverage area 106 and into range of an adjacentcoverage area corresponding to another base station with differentcapabilities. When a 5G SA UE moves from a base station 104 thatsupports 5G NR services to one that only supports 4G LTE, uponinitiating a request for voice services on the 4G LTE base station, theUE voice services module 107A may send a control signal to the fallbackmodule 106A for generating a measurement report and sending the reportto the 4G LTE base station to identify the best fallback frequency andinitiate voice services using that frequency with a base station voiceservices module.

A base station 104 may be maintained by a mobile network operator (MNO)corresponding to the UE 102. The network base station 104 may include aprocessor 104A and a memory 104B storing processor-executableinstructions and data to facilitate a UE 5G/4G fallback process, asdescribed herein. The network base station may also includeprocessor-executable instructions to facilitate the MNO registering UEsand maintaining the network. For example, the memory 1046 may includedata to define a coverage area 106 having a center point X1, Y1 andhaving a radius 108. The base station 104 may also have one or moreradios supporting communication with the UE 102. The base station 104may also include one or more radios operating at different frequencybands and cellular communications standards (e.g., 4G, 5G, etc.)supporting communication with the UE 102 as well as other processors andmemories storing processor-executable instructions for implementing thevarious modules, blocks, functions, data structures, etc., as hereindescribed. The memory 104B may include a base station voice servicesmodule 105 including instructions for execution by the processor 104B toinitiate and maintain voices services including receiving a measurementreport 110 from the UE fallback module 106A or the UE voice servicesmodule 107A upon the 5G UE 102 requesting voice services from the UEvoice services module 107A.

The system 100 generally and the fallback module 106A of the UE 102 inparticular may include processor-executable instructions toautomatically identify signals that are currently accessible for the UE102, determine a signal strength for each of those signals, anddetermine a reliability measurement for each signal, and other metricsfor the measurement report 110. The module 106A may also includeinstructions to receive a control signal from the UE voice servicesmodule 107A which causes the processor 108 of the UE 102 to executeinstructions to send the measurement report 110 to the base station 104and the base station voice services module 105. In some embodiments, theprocessor 104A may execute instructions of the memory 1046 toautomatically send a control signal to the user equipment in response toreceiving the measurement report 110 that indicates a best frequency forinitiating voice services with the UE. The control signal may be forreceiving the service at the user equipment using one of the pluralityof frequencies of the measurement report 110 at the user equipment basedon the signal strengths indicated by the measurement report. In furtherembodiments, when the UE requests a service that is not supported by acommunication standard for current communication between the basestation 104 and a UE 102 and fall back is required, the UE 102 may senda control signal for receiving the service at the user equipment usingone of the plurality of frequencies at the user equipment based on thesignal strengths indicated by the most recent measurement report.

The base station 104 may include several modules or entities (130, 132,134, 136, 138) with processor-executable instructions for facilitatingan authentication and registration process with the UE 102. While thisdisclosure describes five modules (i.e., a Mobile Management Entity(MME) 130, an Access and Mobility Management Function (AMF) 132, anAuthentication Server Function (AUSF) 134, a Unified Data Management(UDM) entity 136, and a Session Management Function (SMF) 138) tofacilitate the authentication and registration processes, persons ofordinary skill in the art will recognize that additional modules andfunctions may be required to complete these processes (see, e.g.,Procedures for the 5G System (5GS) 3GPP TS 29.502 (available at:https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3145).Likewise, functionality of the module or entities may be implemented bya processor executing processor-executable instructions.

Each MNO maintains a Mobile Management Entity (MME) 130 for therespective base station 104, including a Location Register (HLR) fortheir base stations 104. The HLR is a database for the MNO in whichinformation from all mobile subscribers is stored. The HLR containsinformation about the subscribers identity, telephone number, theassociated services for the number or account, and general informationabout the location of the subscriber. The exact location of thesubscriber is kept in a Visitor Location Register (VLR), as describedbelow. The MME 130 is the key control node for the system 100 providingmobility and session management in 4G systems. The MME 130 includesinstructions for idle mode paging and tagging procedure includingretransmissions for the UE 102. The MME 130 also includes instructionsfor activation/deactivation processes and also instructions for choosingthe gateway and base station for the UE 102 at the initial attach and atthe time of intra-LTE handover involving Core Network (CN) noderelocation. The MME 130 also includes instructions for authenticatingthe user by interacting with the respective base station 104.

In 5G systems, the Access and Mobility Management Function (AMF) 132 mayserve part of the role of the MME 130 (i.e., mobility management). TheAMF 132 may maintain a Non-Access Stratum (NAS) signaling connectionwith the UE 102 and manage the UE registration procedure. The AMF 132may also be responsible for paging. In some embodiments, the AMF 132 mayinclude instructions to store configuration and subscription data forthe UE 102 in a local configuration and subscription data repository.

Subscriber authentication, during registration or re-registration with5G, may be managed by the Authentication Server Function (AUSF) 134. TheAUSF may include processor-executable instructions 134A for managingsubscriber authentication during 5G registration. In some embodiments,during registration of the UE 102, the AUSF may obtain various data orauthentication vectors from a local data repository (e.g., SessionManagement Function Data 140, 141, 142 from the Session ManagementFunction data repository 143, etc.). The Session Management FunctionData 140, 141, 142 may include one or more of SMF Selection SubscriptionData and Session Management Subscription Data, including a Data NetworkName array, and other data needed to complete the authentication andregistration processes of various UE 102. In further embodiments, thebase station 104 may retrieve the Session Management Function Data 140,141, 142 from network storage and/or a cloud-based UDM 136.

A Session Management Function (SMF) 138 may provide session managementfunctionality in 5G systems as well as some control plane functions. TheSMF 138 may include instructions 138A to allocate IP addresses to the UE102 during a registration process. The SMF 138 is primarily responsiblefor interacting with the decoupled data plane, creating, updating, andremoving Protocol Data Unit (PDU) sessions and managing session contextwith the User Plane Function (UPF).

During registration of UE with the base station 104, the AMF 132 mayreceive registration requests from UE including the measurement report110 and handle anything to do with connection or mobility managementwhile forwarding session management requirements to the SMF 138. In someembodiments, the base station 104 queries the UDM 136, and the AMF maydetermine which SMF is best suited to handle the connection request byalso querying the UDM 136. The UDM 136 may be stateless and storeinformation externally in a Unified Data Repository (UDR) 137. Methodsand entities for the UDM 136 to use services may be specified in 3GPP TS29.504 and 3GPP TS 29.505 to retrieve configuration and subscriptiondata and Session Management Function Data from the UDR 137 (available athttps://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3405andhttps://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3406,respectively).

Current registration methods retrieve group Session Management FunctionData 140, 141, 142 from the UDR 137 for each UE 102 that registers withthe system 100. The retrieved data is then stored locally before,during, or after processing an incoming UE registration request. In someembodiments, the SMF 138 may include instructions 138A to retrieve groupSelection Subscription Data 140, Session Management Subscription data141, and a Data Network Name Array 142 for registration from a local SMFdata repository 143 or the cloud-based UDM 136. Processing the incomingrequest may then include updating one or more of the SelectionSubscription Data 140, Session Management Subscription data 141, andData Network Name Array 142 in the SMF data repository 143 or UDM 136 orsubscribing to change notifications at the SMF data repository 143 byconsuming the appropriate services. In further embodiments, the SMF 138may also include instructions to perform the role of Dynamic HostConfiguration Protocol (DHCP) server and IP Address Management (IPAM)system. Further, the SMF data repository 143 may maintain a record ofProtocol Data Unit (PDU) session state by means of a 24 bit PDU SessionID. The SMF may also set configuration parameters that define trafficsteering parameters and ensure the appropriate routing of packets whileguaranteeing the delivery of incoming packets, though a Downlink (DL)data notification. The SMF 138 also includes instructions to checkwhether the UE requests are compliant with the user subscription and forconnectivity charging, which is achieved by interacting with a ChargingFunction (CHF).

Processing and network latency during 5G UE registration in VoEPSFBprocedures may be reduced by a modified registration process in whichthe 5G UE sends a measurement report as part of a fallback process forinitiating voice services with a base station 104 that does not include5G voice services. In some embodiments, entities of the system 100, mayinclude processor-implemented instructions to store and use themeasurement report 110 once it is received at the base station 104. Forexample, the processor-implemented instructions may include storing ameasurement report 110 that is associated with each UE that requestsvoice services from the base station.

Each UE may include a UE ID 136A. In some embodiments, the UE ID is apointer to the Session Management Function Data 140 corresponding to theUE 102. Session Management Function Data 140 may be stored locally. Forexample, the system 100 may include processor-executable instructions tostore Session Management Function Data 140 at the SMF data repository143 for the entity requesting the data for registration or otherservices of the system 100. The Session Management Function Data 140 maybe stored locally with the SMF 138, or other entity. One or moreentities of the system 100 may include instructions to pass its UE ID(e.g., subscriber identification or SUPI, a Permanent EquipmentIdentifier of PEI, a Globally Unique Temporary Identifier or GUTI, asubscription concealed identifier or SUCI, an Internal Group Identifier,a General Public Subscription Identifier, an access point name (APN) ora data network name (DNN) linked to its IP address, etc.) to variousentities of the system 100 (e.g., one or more of the Mobile ManagementEntity (MME) 130, the Access and Mobility Management Function (AMF) 132,the Authentication Server Function (AUSF) 134, the Session ManagementFunction (SMF) 138, etc.). The system 100 may cause a processor toexecute these instructions when a UE 102 attempts registration with thesystem 100. The system 100 may include further instructions to identifythe type or capabilities of the UE (e.g., 5G, 4G, etc.) using thereceived UE ID. For example, the SMF may include instructions to receivea UE ID during or in response to registration of the UE. The SMF mayinclude processor-executable instructions to pass the UE ID to the UDM.The UDM 136 may include further processor-executable instructions toidentify the registering UE based on or in response to the received UEID and pass other information (capabilities, software versions, etc.)about the UE back to the system entity (i.e., the SMF 138). The SMF 138or other system entity may include further instructions to use thereceived UE ID to access and apply locally-stored Session ManagementFunction Data 140 for the registering UE.

As previously described, UEs making Voice over New Radio (VoNR) callsfrom the 5G cell edge have a high risk of experiencing bad call qualityand call drops. To prevent this, the UE is forced by the 5G core network(5GC) during the voice call setup to switch to a LTE/EPS connectionwhere the radio conditions are better for the voice service. The sameproblems also occur when the UE is served by a 5G cell that is notconfigured or optimized for VoNR calls or when the UE does not have allneeded VoNR capabilities. To implement this procedure, the 5G radioconnection may be released after the initial call attempt issuccessfully finished and the base station 104 may send a control signalto the UE 102 for reselecting to a 4G cell where a new radio connectionis started for the VoLTE call. The UE context may then be transferredfrom the AMF 132 to the MME 130 over the N26 interface. In furtherembodiments, the session management and user plane tunnels in the corenetwork may also be handed over from SMF/UPF to MME/S-GW. Theseprocedures introduce a call setup delay of approximately two seconds.

To eliminate this delay, the fallback module 106A of the UE 102 mayinclude instructions to define a call initiation event to trigger takingor sending a measurement report 110 from the UE 102 to the base station104 in response to initiating a call from the UE. Various events formeasurement report triggering for the UE 102 may be described in 3GPP TS38.331 “Radio Resource Control (RRC) protocol specification” (availableat:https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3197).To optimize EPS fallback procedures, instructions of the system 100 maydefine a call initiation event that causes the processor 108 to send acontrol signal to the fallback module 106A upon initiating a voiceservices request of the voice services module 107A to the base station104 from the UE 102. In some embodiments, instructions of the UE 102 mayinitiate the procedure when the voice services module 107A causes upperlayers to request establishment of a Radio Resource Control (RRC)connection. For example, the UE 102 may send a control signal to thebase station 104 including a command to establish an RRC connection anda measurement report 110. The control signal from the UE 102 may includean “RRCSetupRequest” instruction for the base station 104 with themeasurement report 110. The base station 104 may also includeinstructions to perform a number of actions upon receiving the“RRCSetupRequest” message and establish voice services with the UE 102.For example, the instructions may include analyzing the measurementreport 110 to determine an optimal channel for 4G EPSFB. An optimalchannel may include a frequency indicated in the measurement report 110as having one or more of the highest signal strength and reliability.Once the base station 104 determines an optimal channel, the basestation 104 may send a control signal to the UE 102 to join the optimalchannel via a “RRCSetup” message. Further instructions of the UE 102 maysend an “RRCSetupComplete” message back to the base station 104 once theUE 102 has established communications with the optimal channel indicatedin the measurement report 110.

FIG. 2 illustrates an exemplary block diagram of a base station 104 inaccordance with the current disclosure. The base station 104 may includea processor 230 that is in communication with a memory 232. The memory232 may include an operating system and utilities 234 used to manageoperations of the base station including booting, memory management,communications, UE registration, error handling, software updates, etc.The memory 232 may also store processor-executable instructions 236 anddata 244.

The base station 104 may have a radio 250 operating at a frequency bandthat provides for a coverage area 106 (FIG. 1) larger than that ofanother frequency band in use by the network base station 104. Forexample, another base station may operate in a frequency band in the 700MHz frequency range with a larger coverage radius. In many prior artsystems, wide area coverage was provided by an overlapping network ofsimilar band radios, operating at up to 2.5 GHz, but having similarcoverage areas. 4G LTE is such an example. In such systems, the UE 102may tell one base station when it is getting a stronger signal fromanother base station so that a handoff between base stations can beexecuted.

However, in the new 5G (fifth generation cellular) standard, a mixedsystem of low band (e.g., 700 MHz base stations) may be intermixed withmillimeter wave radios operating in frequency bands around 50 GHz. Theseso called NR (new radio) radios may have a coverage radius of 500 metersor less depending on terrain and other obstructions. Unlike previoussystems, the 5G implementation mixes these bands with significantlydifferent coverage areas. The base station 104 may also include anetwork interface 252 used for routing traffic from land-based switchgear (not depicted). The network interface 252 may also communicate withan external data source 254.

The executable instructions 236 may include various modules or routinesthat are used for registering UE and establishing VoEPSFB services asdescribed herein. The memory 232 may include one or more of the MME 130,the AMF 132, the AUSF 134, and the SMF 138. The data 244 may includeSession Management Function Data 140, and other data such as SessionManagement Subscription data 141, a Data Network Name Array 142, etc.The data 244 may also include coverage coordinates or descriptors,capabilities (e.g., 2G, 3G, 4G, or 5G, narrow band, etc.) of thecoverage areas of the base stations and coverage coordinates for otherbase stations (not depicted) having small coverage areas compared tothat of the other network base stations.

An embodiment of a UE 102 may be illustrated in FIG. 3. The UE 102 maybe a cellular telephone, a tablet, a laptop, IoT device, etc. In othercases, the UE 102 may be any of a number of items that increasingly relyon network connectivity, such as a smartphone, internet of thingsdevice, vehicle, or other device. The UE 102 may include a processor 360and memory 362 including an operating system and utilities 364,executable code 366 that may include both native and downloadedapplications, and data memory 368. The data memory 368 may include a UEID (e.g., subscriber identification or SUPI, a Permanent EquipmentIdentifier of PEI, a Globally Unique Temporary Identifier or GUTI, asubscription concealed identifier or SUCI, an Internal Group Identifier,a General Public Subscription Identifier, an access point name (APN) ora data network name (DNN) linked to its IP address, etc.) and specificdevice capabilities, such as coordinates or a descriptor as describedabove. The data memory 368 may also include the measurement report 110as described herein. The UE 102 may also include a user interface 370that itself may incorporate a display 372 and input device 374 such as akeyboard or touchscreen.

A location unit 376 may include a GPS receiver but may also rely on celltower triangulation, Wi-Fi positioning (WPS), or other locationtechniques. Unlike the currently disclosed system, Wi-Fi positioning mayrequire a mobile device to constantly monitor for Wi-Fi SSID and MACaddresses and use those with an external database to infer the locationof the device from the location the Wi-Fi access point.

FIG. 4 is a flowchart of a computer-implemented method 400 forcompleting one or more processes for completing a “fallback” procedurebetween a 5G-capable UE 102 and a base station 104. As described herein,logic in the 5G UE may send a measurement report 110 to the 5G basestation 104 (i.e., gNB) while the 5G SA UE 102 is going through a callsetup requiring “fallback” (e.g., VoEPSFB). A new event and measurementreport 110 may convey the most current available frequencies (3G, 4G, 4GLTE, etc.) to the 5G base station 104 while the 5G UE 102 is goingthrough a call setup. This measurement report 110 may allow the 5G basestation (g-NB) 104 to know which frequency is going to be the bestchoice at the time of setting up the voice service by looking at radiosignal strength indicators and other measurements or data coming fromthe 5G UE 102 for each frequency in the measurement report 110. Thatway, a 5G base station 104 can make the right choice to automaticallysend a control signal to the 5G UE 102 to join the optimal LTE frequencyinstead of sending a blind choice of any available 4G frequency based onprior measurement reports that frequently include out-of-dateinformation or incomplete. Using the measurement report 110 sent by theUE 102 upon voice services initiation, the 5G base station 104 mayoptimally control a 5G UE 102 without having available frequencies tosupport the requested service (e.g., voice services) in 5G NR. The 5Gbase station 104 may cause the 5G UE 102 to move to a strong andreliable radio signal strength indicated in the measurement report 110to make voice calls over 4G using that stronger signal. As such, the 5GUE 102 may have faster call setup time by having such enhanced logic in5G UE 102 so that it proactively helps the 5G base station 104 to assignit to the right frequency during a voice call setup. Incorporating themeasurement report process into the logic of the 5G UE 102 for callsetup that also includes the fallback process may result insubstantially faster call setup time as well as better voice callsuccess rate.

Each step of the method 400 is one or more computer-executableinstructions (e.g., modules, blocks, stand-alone instructions, etc.)performed on a processor of a server or other computing device (e.g.,base station 104, UE 102, other computer system illustrated in FIG. 1and/or described herein) which may be physically configured to executethe different aspects of the method. Each step may include execution ofany of the instructions as described in relation to the system 100 aspart of the cellular network registration systems and methods describedherein or other component that is internal or external to the system100. While the below blocks are presented as an ordered set, the varioussteps described may be executed in any particular order to complete themethods described herein.

At block 402, the computer-implemented method 400 may determine aconnection mode for the UE 102. As described above, the RRC protocol isused to control radio connections between the UE 102 and the basestation 104. A state machine defines three different RRC states:inactive, idle, and connected. When the UE 102 is in connected or idlemode, the method 400 may continue to monitor the connection mode atblock 402. When the UE 102 is in inactive mode, the method 400 may causethe system 100 to execute an instruction to request or re-establishservices (e.g., the RRC connection) at block 404. For example, the UE102 may execute instructions to send an “RRCSetupRequest” message thatincludes the measurement report 110 to the base station 104. Executionof block 404 may trigger a call initiation event for a measurementreport 110. The call initiation event may cause the method 400 toexecute instructions of block 406 to compile a measurement report 110.In some embodiments, the method 400 may execute instructions of block406 to compile the measurement report 110 in response to or upon the UErequesting or re-establishing services. Execution of block 406 may causethe UE 102 to compile the measurement report 110 including dataindicating frequencies that are currently being received by the UE 102,a signal strength for each of those frequencies, an indication of astandard for the signal (e.g., 4G LTE, 4G, 3G, etc.), a duration ofsignal reception at the UE 102, a measure of signal reliability eitherat the UE 102 or other data that may be determined from past measurementreports 110, among other information. In some embodiments, the signalstrength is indicated in decibel-milliwatts (dBm) in the measurementreport. In some embodiments, frequency is indicated on the measurementreport 110 in gigahertz (GHz). In other embodiments, frequency may beindicated in any other suitable units of measurement.

At block 408, the method 400 may send the measurement report 110 to thebase station 104. In some embodiments, the measurement report 110 issent from the UE 102 to the base station 104 with an “RRCSetupRequest”message. In response to the measurement report 110 and other setupinstructions, the base station 104 may send a control signal to the UE102 to attach to the optimal frequency indicated in the measurementreport 110 that was sent to the base station at block 404. In someembodiments, the control signal includes an “RRCSetup” message from thebase station 104.

At block 410, in response to execution of block 408, the UE 102 mayexecute instructions to attach to the to the optimal frequency indicatedin the measurement report 110. In some embodiments, the UE 102 may causeits processor to execute instructions to enter an “RRC_CONNECTED” state,stop the cell re-selection procedure, set the contents of an“RRCSetupComplete” message, and send that message to the base station104. Once the UE 102 is connected to the optimal frequency indicated inthe measurement report 110, the method 400 may return to block 402 tocontinue monitoring for the UE 102 to enter the inactive state.

Thus, the present application describes a technical solution to thetechnical problem of call setup delays, signal drops, and other issuesduring fallback procedure from 5G to 4G protocols. Logic in the 5G UE102 may send a measurement report 110 to the 5G base station 104 (i.e.,gNB) in response to the event of the 5G SA UE 102 initiating a callsetup using VoEPSFB. This new type of event and measurement report 110may convey the most current available frequencies (3G, 4G, 4G LTE, etc.)to the 5G base station 104 while the 5G UE 102 is going through a callsetup. This measurement report 110 may allow the 5G base station 104(g-NB) to know which frequency is going to be the best choice at thetime of setting up the voice service by looking at radio signal strengthindicators coming from the 5G UE 102 for each frequency in themeasurement report 110. That way, a 5G base station 104 can make theright choice to automatically send a control signal to the 5G UE 102 tojoin the optimal LTE frequency instead of sending a blind choice of anyavailable 4G frequency based on prior measurement reports or other datathat frequently include out-of-date information. Using the measurementreport 110 compiled and sent by the UE 102 upon voice servicesinitiation, the 5G base station 104 may optimally control 5G UE 102without having available frequencies to support the requested service(e.g., voice services) in 5G NR. The 5G base station 104 may cause the5G UE 102 to move to a strong and reliable radio signal strengthindicated in the measurement report 110 to make voice calls over 4Gusing that stronger signal. As such, the 5G UE 102 may have faster callsetup time by having such enhanced logic in 5G UE 102 so that itproactively helps the 5G base station 104 to assign it to the rightfrequency during a voice call setup. Incorporating the measurementreport 110 process into the logic of the 5G UE 102 for call setup thatalso includes the fallback process for 5G UE 102 may result insubstantially faster call setup time as well as better voice callsuccess rate.

Additionally, certain embodiments are described herein as includinglogic or a number of components, modules, blocks, or mechanisms. Modulesand method blocks may constitute either software modules (e.g., code orinstructions embodied on a machine-readable medium or in a transmissionsignal, wherein the code is executed by a processor) or hardwaremodules. A hardware module is tangible unit capable of performingcertain operations and may be configured or arranged in a certainmanner. In example embodiments, one or more computer systems (e.g., astandalone, client or server computer system) or one or more hardwaremodules of a computer system (e.g., a processor or a group ofprocessors) may be configured by software (e.g., an application orapplication portion) as a hardware module that operates to performcertain operations as described herein.

In various embodiments, a hardware module may be implementedmechanically or electronically. For example, a hardware module maycomprise dedicated circuitry or logic that is permanently configured(e.g., as a special-purpose processor, such as a field programmable gatearray (FPGA) or an application-specific integrated circuit (ASIC)) toperform certain operations. A hardware module may also compriseprogrammable logic or circuitry (e.g., as encompassed within a processoror other programmable processor) that is temporarily configured bysoftware to perform certain operations. It will be appreciated that thedecision to implement a hardware module mechanically, in dedicated andpermanently configured circuitry, or in temporarily configured circuitry(e.g., configured by software) may be driven by cost and timeconsiderations.

Accordingly, the term “hardware module” should be understood toencompass a tangible entity, be that an entity that is physicallyconstructed, permanently configured (e.g., hardwired), or temporarilyconfigured (e.g., programmed) to operate in a certain manner or toperform certain operations described herein. As used herein,“hardware-implemented module” refers to a hardware module. Consideringembodiments in which hardware modules are temporarily configured (e.g.,programmed), each of the hardware modules need not be configured orinstantiated at any one instance in time. For example, where thehardware modules comprise a processor configured using software, theprocessor may be configured as respective different hardware modules atdifferent times. Software may accordingly configure a processor, forexample, to constitute a particular hardware module at one instance oftime and to constitute a different hardware module at a differentinstance of time.

Hardware modules can provide information to, and receive informationfrom, other hardware modules. Accordingly, the described hardwaremodules may be regarded as being communicatively coupled. Where multipleof such hardware modules exist contemporaneously, communications may beachieved through signal transmission (e.g., over appropriate circuitsand buses) that connect the hardware modules. In embodiments in whichmultiple hardware modules are configured or instantiated at differenttimes, communications between such hardware modules may be achieved, forexample, through the storage and retrieval of information in memorystructures to which the multiple hardware modules have access. Forexample, one hardware module may perform an operation and store theoutput of that operation in a memory device to which it iscommunicatively coupled. A further hardware module may then, at a latertime, access the memory device to retrieve and process the storedoutput. Hardware modules may also initiate communications with input oroutput devices, and can operate on a resource (e.g., a collection ofinformation).

The various operations of example methods described herein may beperformed, at least partially, by one or more processors that aretemporarily configured (e.g., by software) or permanently configured toperform the relevant operations. Whether temporarily or permanentlyconfigured, such processors may constitute processor-implemented modulesthat operate to perform one or more operations or functions. The modulesreferred to herein may, in some example embodiments, compriseprocessor-implemented modules.

Similarly, the methods or routines described herein may be at leastpartially processor-implemented. For example, at least some of theoperations of a method may be performed by one or processors orprocessor-implemented hardware modules. The performance of certain ofthe operations may be distributed among the one or more processors, notonly residing within a single machine, but deployed across a number ofmachines. In some example embodiments, the processor or processors maybe located in a single location (e.g., within an environment, an officeenvironment or as a server farm), while in other embodiments theprocessors may be distributed across a number of locations.

The one or more processors may also operate to support performance ofthe relevant operations in a “cloud computing” environment or as a“software as a service” (SaaS). For example, at least some of theoperations may be performed by a group of computers (as examples ofmachines including processors), these operations being accessible via anetwork (e.g., the Internet) and via one or more appropriate interfaces(e.g., application program interfaces (APIs).)

The performance of certain of the operations may be distributed amongthe one or more processors, not only residing within a single machine,but deployed across a number of machines. In some example embodiments,the one or more processors or processor-implemented modules may belocated in a single geographic location (e.g., within an environment, anoffice environment, or a server farm). In other example embodiments, theone or more processors or processor-implemented modules may bedistributed across a number of geographic locations.

Some portions of this specification are presented in terms of algorithmsor symbolic representations of operations on data stored as bits orbinary digital signals within a machine memory (e.g., a computermemory). These algorithms or symbolic representations are examples oftechniques used by those of ordinary skill in the data processing artsto convey the substance of their work to others skilled in the art. Asused herein, an “algorithm” is a self-consistent sequence of operationsor similar processing leading to a desired result. In this context,algorithms and operations involve physical manipulation of physicalquantities. Typically, but not necessarily, such quantities may take theform of electrical, magnetic, or optical signals capable of beingstored, accessed, transferred, combined, compared, or otherwisemanipulated by a machine. It is convenient at times, principally forreasons of common usage, to refer to such signals using words such as“data,” “content,” “bits,” “values,” “elements,” “symbols,”“characters,” “terms,” “numbers,” “numerals,” or the like. These words,however, are merely convenient labels and are to be associated withappropriate physical quantities.

Unless specifically stated otherwise, discussions herein using wordssuch as “processing,” “computing,” “calculating,” “determining,”“presenting,” “displaying,” or the like may refer to actions orprocesses of a machine (e.g., a computer) that manipulates or transformsdata represented as physical (e.g., electronic, magnetic, or optical)quantities within one or more memories (e.g., volatile memory,non-volatile memory, or a combination thereof), registers, or othermachine components that receive, store, transmit, or displayinformation.

As used herein any reference to “some embodiments” or “an embodiment” or“teaching” means that a particular element, feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. The appearances of the phrase “in someembodiments” or “teachings” in various places in the specification arenot necessarily all referring to the same embodiment.

Some embodiments may be described using the expression “coupled” and“connected” along with their derivatives. For example, some embodimentsmay be described using the term “coupled” to indicate that two or moreelements are in direct physical or electrical contact. The term“coupled,” however, may also mean that two or more elements are not indirect contact with each other, but yet still co-operate or interactwith each other. The embodiments are not limited in this context.

Further, the figures depict preferred embodiments for purposes ofillustration only. One skilled in the art will readily recognize fromthe following discussion that alternative embodiments of the structuresand methods illustrated herein may be employed without departing fromthe principles described herein

Upon reading this disclosure, those of skill in the art will appreciatestill additional alternative structural and functional designs for thesystems and methods described herein through the disclosed principlesherein. Thus, while particular embodiments and applications have beenillustrated and described, it is to be understood that the disclosedembodiments are not limited to the precise construction and componentsdisclosed herein. Various modifications, changes and variations, whichwill be apparent to those skilled in the art, may be made in thearrangement, operation and details of the systems and methods disclosedherein without departing from the spirit and scope defined in anyappended claims.

The invention claimed is:
 1. An apparatus for completing a fallbackprocess between a base station and a user equipment in a cellularnetwork, the apparatus comprising: a user equipment including aprocessor and a memory storing instructions for execution by theprocessor for: sending a request to initiate a 5G voice serviceprocedure with the base station; upon sending the request to initiatethe 5G voice service procedure with the base station: determining asignal strength for each of a plurality of fallback frequencies beingreceived by the user equipment; generating a measurement reportincluding the signal strength for each of the plurality of fallbackfrequencies being received by the user equipment; sending themeasurement report to the base station; receiving a control signal fromthe base station; and attaching, in response to the control signal fromthe base station, to an optimal one of the plurality of fallbackfrequencies at the user equipment, the optimal one of the plurality offallback frequencies having a highest signal strength of each of theplurality of fallback frequencies indicated by the measurement report;wherein the control signal indicates that a frequency for a 5G servicecorresponding to the 5G service procedure is not supported by the basestation.
 2. The apparatus of claim 1, wherein the measurement reportfurther includes a reliability for each of the plurality of frequenciesbeing received by the user equipment.
 3. The apparatus of claim 2,wherein the optimal one of the plurality of frequencies includes afrequency indicated in the measurement report as having a highest signalstrength and reliability.
 4. The apparatus of claim 3, wherein the basestation is further configured to automatically send a further controlsignal to the user equipment in response to receiving the measurementreport, the further control signal for the user equipment to receivecommunication on the optimal one of the plurality of frequencies.
 5. Theapparatus of claim 1, wherein the user equipment is configured toprocess a 5G NR signal.
 6. The apparatus of claim 1, wherein themeasurement report includes data indicating one or more of frequenciesthat are currently being received by the user equipment, a signalstrength for each of the one or more frequencies, an indication of astandard for each of the one or more frequencies, the standard for eachof the one or more frequencies including one of 4G LTE, 4G, and 3G, aduration of signal reception for each of the one or more frequencies atthe user equipment, a measure of signal reliability for each of the oneor more frequencies at the user equipment.
 7. The apparatus of claim 1,wherein determining the signal strength for each of the plurality offrequencies being received by the user equipment includes determiningthe signal strength for each of the plurality of frequencies beingreceived by the user equipment when the user equipment enters aninactive state.
 8. The apparatus of claim 1, wherein sending themeasurement report to the base station upon sending the request toinitiate the service corresponding to the measurement report includessending the measurement report with an RRCSetupRequest message.
 9. Theapparatus of claim 1, wherein the control signal includes an RRCSetupmessage.
 10. The apparatus of claim 1, further comprising sending anRRCSetupComplete message to the base station in response to the userequipment attaching to the optimal one of the plurality of frequenciesin response to the RRCSetup message.
 11. A computer-implemented methodfor completing a fallback process between a base station and a userequipment in a cellular network, the computer-implemented methodcomprising: sending a request from the user equipment to initiate a 5Gvoice service procedure with the base station; upon sending the requestto initiate the 5G voice service procedure with the base station, at theuser equipment: determining a signal strength for each of a plurality offallback frequencies being received by the user equipment; generating ameasurement report including the signal strength for each of theplurality of fallback frequencies being received by the user equipment;sending the measurement report to the base station; receiving a controlsignal from the base station at the user equipment; attaching, inresponse to the control signal from the base station, to an optimal oneof the plurality of fallback frequencies at the user equipment, theoptimal one of the plurality of fallback frequencies having a highestsignal strength of each of the plurality of fallback frequenciesindicated by the measurement report; wherein the control signalindicates that a frequency for a 5G service corresponding to the 5Gservice procedure is not supported by the base station.
 12. Thecomputer-implemented method of claim 11, wherein the measurement reportfurther includes a reliability for each of the plurality of frequenciesbeing received by the user equipment.
 13. The computer-implementedmethod of claim 12, wherein the optimal one of the plurality offrequencies includes a frequency indicated in the measurement report ashaving a highest signal strength and reliability.
 14. Thecomputer-implemented method of claim 13, further comprising receiving afurther control signal from the base station at the user equipment inresponse to receiving the measurement report, the further control signalfor the user equipment to receive communication on the optimal one ofthe plurality of frequencies.
 15. The computer-implemented method ofclaim 11, wherein the user equipment is configured to process a 5G NRsignal.
 16. The computer-implemented method of claim 11, wherein themeasurement report includes data indicating one or more of frequenciesthat are currently being received by the user equipment, a signalstrength for each of the one or more frequencies, an indication of astandard for each of the one or more frequencies, the standard for eachof the one or more frequencies including one of 4G LTE, 4G, and 3G, aduration of signal reception for each of the one or more frequencies atthe user equipment, a measure of signal reliability for each of the oneor more frequencies at the user equipment.
 17. The computer-implementedmethod of claim 11, wherein determining the signal strength for each ofthe plurality of frequencies being received by the user equipmentincludes determining the signal strength for each of the plurality offrequencies being received by the user equipment when the user equipmententers an inactive state.
 18. The computer-implemented method of claim11, wherein sending the measurement report to the base station uponsending the request to initiate the service corresponding to themeasurement report includes sending the measurement report with anRRCSetupRequest message.
 19. The computer-implemented method of claim11, wherein the control signal includes an RRCSetup message.
 20. Thecomputer-implemented method of claim 11, further comprising sending anRRCSetupComplete message to the base station in response to the userequipment attaching to the optimal one of the plurality of frequenciesin response to the RRCSetup message.